GSXR250R (GJ73A) Race Bike Build

It's a never ending battle of maintenance hey! Same story here...been machining all week and haven't had any time to look at the Ciblet. No doubt I need every advantage I can get at the moment the way you have been riding!

 

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Paint is looking nice Si.
Yet more problems with mine. Turns out the eBay back wheel I bought is a different size hub!... Bollox.
Think it's off a 400. Got hold of the right sprocket carrier and Cush drive rubbers, so hoping this week to get it sorted and in for a MOT. Just want to get some miles in on it now can do all the cosmetics at a later date.
Did you get hold of all those parts from Si in Scotland?

 

Got that 'new' engine ( well 2nd hand but not far off NOS at under 2K miles of him lol)..the rest of the stuff I've got is over the years surplus stuff plus numerous rebuilds on the same bikes..should have whatever you need mate so just ask..I think im on about the eighth or ninth now m8..no 18 inch rear im afraid but I could get you one given a week or so..can machine you a hub/hub carrier to suit if need be..good base is to know what its come from though..I can do some digging m8 from that and a parts no. but otherwise I've got a few magnesium billets around and a cnc machinist in work who can do wonders via cad..pretty much easy with the microfische templates but wouldn't like to try without lol!! A gsxr 400 (73) should go straight on but you might need to 'reem' it slightly..sure the 400 (76) ull do much the same on a 17 inch rear as i've done that one before and if your going to change again then that's what i'd go for as u'll get better tyre choice and you'll be able to go upto a 150/160 rear..same as on my track bike..paint looked good but many hours of slaving away has brought some proper good results..I never wielded a spray gun at any point so credit where credits due DAVE..and thanks for making me bow down to the fact that your current and i'm not..water vs solvent..I owe you a pint (or several) for three hours in the oven!!! I'm so so hoping this turns out like yours m8...and boyd..don't bow down to pressure..any advantage is just that..a means to get ahead..god knows with no torque we need it!!!!

 

wow its looking good, as Sport Production paint job, I cant wait to see how it will´.

 

The paint is looking mint, you've obviously got a lad who knows his stuff with a spray gun.
Think I've finally sorted my back wheel problems. Made a new spacer last night at work, so hoping to get a ticket on it this week.
Looking back on it I would have been better off going down the 17 inch wheel route, still you live and learn eh?

 

Shark fin awaits your arrival along with carb balancer and your carb balancing skills But seriously when and if I actually ever get that far a hand with balancing the carbs on the ciblet would be awesome! I actually got her back together the other day but now waiting on a Chinese replica fuel pump so I can start her up. Running a bit behind compared to you and the Gixlet!

 

Well mines back on the road all legal and legit. Took advantage of the good weather the other weekend to get a few miles in. All went well until the key snapped off in the petrol cap!!! 2 1/2 hours and 65 quid later (auto locksmith) I was back on the road.
Off to the Isle of Man on it in 3 weeks time so will see how it (and me) get on around the TT course.. Whey hey....!
Going to leave the cosmetic stuff until later in the year now, time to get some miles in. How's yours progressing? The paint is looking really nice.

 

Cheers matey..all good this side too..don't blame yus for taking advantage of the weather of late..been doing much the same too!! seen your post on the other thread ref mirrors and fuse box..dug out a fusebox minus cover which yus can have foc..no mirrors though - there still available oem but £70 plus quid each..next time I need some i'm going down the aftermarket route lol..fuse box inc cover is same as gsxf one's that are far more common! IOM you lucky b****rd!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! All the best mate speak soon fella

Cheers si

 

Cheers for that Si,
Got a gsxf fuse box cover off ebay.
Not so sure about being a lucky b***ard. Bikes running like a sack of s**t. Still suffering from fuel starvation at high revs. Which looks like it's a fuel tap problem (it won't flow on prime) think I'll take the vacuum bit out and see what happens.
Cleaned all the carbs out which has improved things. Do you know what the float heights and idle screw settings should be (anyone). Next thing is to order a carb oring set from Thailand of all places, won't be here before iom though.
I'd appreciate your thoughts.
Ta mate

 

Aye up m8 good to hear of yus..not so good hearing of the bike issues..but they strike us all lol ..but were not all going to the IOM I'll do whatever I can to help yus m8 before you go..wish I could get the time off as I'd be on the same boat!!!!!! Chin up anways here's the info you need - Idle screw settings as stock (manual) are 'all in, then 1 1/2 out'..usual stuff about not being hamfisted with the screws as yes they will damage the seat. Depends on the specific bike but most I've worked on with the standard pilot screws are best one to one and a quarter out..best to balance the carbs while your at it as there bound to be off and it makes a massive difference to pick up on these motors. The carb kit is top notch if its the one from litetek....fits no problems..deffo balance the carbs again once the full kits are on though! Had a lot of trouble with the petcocks known issue as they leak..and no longer available..and you try finding one new used or otherwise..its nigh on impossible! I'll dig you out a part number tmoz as I cant remember of the top of my head which rebuild kit fits it - poss a dt125 or a dr125 for the petcock to tank seal and gsxr 400 diaphragm..the bike will run differently if the vacuum pipe is totally disconnected..you'll see this when your balancing the carbs..float heights are 8.06mm + or minus 1mm..I kid you not on this one..I've never seen specs go down to two decimal places before but there you go..they seem to run fine at 8mm as that's as good as I could measure..none of them have ever needed adjusting on the ones I've done though as the float assemblys a bit more robust than most..good luck fella and keep us posted on any developments..if I can help I will..also got spare carbs here if you get stuck or if you find yours are damaged/need new parts from whoever had it last..

Got a wiring loom problem on mine at the mo..runs fine..but then has a fit and pretty much stalls under load and throws out white smoke/condensation..i couldnt replicate the fault to trace it as it came and went..but luck would have it it did it Monday just gone as I went down the drive returning home..straight into the garage tank off engine still running..rubber gloves on and played around with pretty much the whole loom..what do you know the main harness under the left coil harbours a dodgy wire..some tooing and froing immediately cleared the miss and the exhaust went back to being normal..my guess is the bad wire was reducing the spark generated so it wasn't burning cleanly..probably breaking down as its so hot by there - read naff design the heat sheilding stops 5cms before the internal fault with the loom..dreading unravelling it..god knows I hate electrics!!!!

 

Thanks for the info Si, much appreciated,
Bikes still running rough but I think it's just the carbs that need balancing. Not sure about the fuel tap though. Can't work it out really. The prime position just seems to rely on the weight of the fuel in the tank to open the tap.
Glad to here you've sorted your problem, I know what you mean about electrics it's a black art to me.
Makes you wonder why we bother keeping these things running doesn't it?

 

message from Andy T

Mines in the bike shop at the moment having the carbs balanced. Only problem is now it won't start!
I say it won't start but sometimes it does and sometimes it doesn't !!!!
Had the same problem this morning before taking it to shop. Squirt of easy start got it going.
I'm thinking that the coils have seen better days. Very weak spark when I checked the plugs in the past.

Sent from my I phone

 

Awesome mate!

 

Hi and thanks for the good topic here, was able to find some nice info thanks to it.

Very nice progress on the bike, thumbs up and keep it up!

I have a question, since I happen to own a GSX 250S Cobra (same engine and frame, just the semi-naked one with the round headlight). It is very low mileage but the carbs are possibly beyond repair and I may need (will find out this week) new piston set, pistons included.

Any idea where can i get new OEM pistons for that engine. I dont have trust in the Chinese ones that were linked here.

Will greatly appreciate any help with that.

If i manage to fix the engine I will probably have quite a lot of spare parts for that bike, since I have the very weird idea to use the frame and engine as a base for a really crazy cafe racer

 

Simon, are you sure about that part? If the GSF 250 pistons STD are identical to the Cobra that would really be very good news, but the Cobra is really a GJ73A, not 74.